4 Symptoms of a Bad Brake Light Switch
Your brakes do more than just slow your car down. Your brake lights should shine brightly too. But if your red tail lights aren’t on when they should be, your brake light switch could be faulty. But that’s not the only symptom.
Learn the most common signs of a faulty brake light switch, what causes it to fail in the first place, and how much it might cost to repair. What is a brake light switch? A brake light switch is a device that provides feedback within certain circuits when the driver depresses the brake pedal. One of the circuits that is closed by the operation of this switch is the brake light circuit.
Simply put, the brake light switch is responsible for directing power through the brake light circuit so that these lights come on when you apply the brakes. Additionally, many vehicles are designed so that the brake light switch can take on additional roles with different importance.
For example, power from the brake light switch is used as a critical input to the car’s cruise control circuit to interrupt the cruise control function when the car brakes are applied. In many cases, feedback from the brake light switch also plays a key role in the shifter lockout circuit.
Symptoms of a faulty brake light switch A fault in your vehicle’s brake light switch is often accompanied by one or more secondary symptoms, some of which may also pose potential safety risks. For this reason, it is especially important to be able to recognize such symptoms immediately when they occur.
Below are some of the most common symptoms associated with a faulty brake light switch:
1) Brake lights not working or functioning abnormally
As the name suggests, the brake light switch turns on the vehicle’s brake lights when the brake pedal is pressed. Therefore, a faulty brake light switch can cause the brake lights to not work or to function abnormally.
2) Cruise control issues
Power to a vehicle’s brake light switch is often routed through the cruise control circuit, which allows the driver to disable cruise control when the driver applies the brakes. A faulty brake light switch often causes the car’s cruise control to work erratically or not at all.
3) Unable to Move Out of Park
In many cases, power from the brake light switch is also sent to the vehicle’s shift lock. As a result, if the brake light switch no longer functions as intended, the vehicle’s shift lock will often not disengage. This simply means that the car will not be able to shift out of Park.
4) ABS or Brake Warning Light
Some vehicles are designed to illuminate a warning light specific to the brake system when the brake light switch circuit fails. This warning light often comes in the form of an ABS light or an illuminated “BRAKE” message. Where is the brake light switch located?
Due to its reliance on a mechanical input when braking, brake light switches are typically located in one of a few different locations, regardless of application.
In most cases, this switch is mounted very close to the vehicle’s firewall, directly at the brake pedal connection itself. In some cases, this switch’s exact location may be further up along the firewall, behind the dashboard.
The brake light switch is located here primarily because of its design. This switch is a piston design, allowing it to turn a circuit on or off depending on a mechanical input. In this case, when the vehicle’s brake pedal is stroked downwards, the brake link itself contacts the brake light switch, providing continuity.
What causes a brake light switch to fail?
The most common cause of brake light switch failure is simple wear and tear. A typical brake light switch will be pressed thousands of times over its lifespan. Over time, the contacts of this switch begin to corrode and continuity is no longer guaranteed. This wear tends to accelerate if your vehicle’s brake light switch is not adjusted correctly, resulting in undue stress.
Additionally, brake light switches that are exposed to excessive dirt and moisture are more likely to fail than those that are not. Therefore, simply keeping your vehicle’s cab clean and dry can help extend the life of such components. This can save you money on car repairs in the long run.
